docs: def check_argument_type(long_form, specification_dict):
      """
      Ensures that long_form is a pandas dataframe and that specification_dict
      is an OrderedDict, raising a ValueError otherwise.
  
      Parameters
      ----------
      long_form : pandas dataframe.
          Contains one row for each available alternative, for each observation.
      specification_dict : OrderedDict.
          Keys are a proper subset of the columns in `long_form_df`. Values are
          either a list or a single string, `"all_diff"` or `"all_same"`. If a
          list, the elements should be:
  
              - single objects that are within the alternative ID column of
                `long_form_df`
              - lists of objects that are within the alternative ID column of
                `long_form_df`. For each single object in the list, a unique
                column will be created (i.e. there will be a unique coefficient
                for that variable in the corresponding utility equation of the
                corresponding alternative). For lists within the
                `specification_dict` values, a single column will be created for
                all the alternatives within iterable (i.e. there will be one
                common coefficient for the variables in the iterable).
  
      Returns
      -------
      None.
      """
      if not isinstance(long_form, pd.DataFrame):
          msg = "long_form should be a pandas dataframe. It is a {}"
          raise TypeError(msg.format(type(long_form)))
  
      ensure_object_is_ordered_dict(specification_dict, "specification_dict")
  
      return None